title: Fewer ligament injuries but no preventive effect on muscle injuries and severe injuries: an 11-year follow-up of the UEFA Champions League injury study.
abstract: BACKGROUND
  Limited information is available on the variation in injury rates over multiple seasons of professional football.
  
  
  OBJECTIVE
  To analyse time-trends in injury characteristics of male professional football players over 11 consecutive seasons.
  
  
  METHODS
  A total of 1743 players comprising 27 teams from 10 countries were followed prospectively between 2001 and 2012. Team medical staff recorded individual player exposure and time loss injuries.
  
  
  RESULTS
  A total of 8029 time loss injuries were recorded. The match unavailability due to injury was 14% and constant over the study period. On average, a player sustained two injuries per season, resulting in approximately 50 injuries per team and season. The ligament injury rate decreased during the study period (R(2)=0.608, b=-0.040, 95% CI -0.065 to -0.016, p=0.005), whereas the rate of muscle injury (R(2)=0.228, b=-0.013, 95% CI -0.032 to 0.005, p=0.138) and severe injury (R(2)=0.141, b=0.015, 95% CI -0.013 to 0.043, p=0.255) did not change over the study period. In addition, no changes in injury rates over the 11-year period were found for either training (R(2)=0.000, b=0.000, 95% CI -0.035 to 0.034, p=0.988) or match play (R(2)=0.282, b=-0.015, 95% CI -0.032 to 0.003, p=0.093).
  
  
  CONCLUSIONS
  The injury rate has decreased for ligament injuries over the last 11 years, but overall training, match injury rates and the rates of muscle injury and severe injury remain high.
authors.affiliation: Division of Community Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden. jan.ekstrand@telia.com
authors.forename: Jan
authors.initials: J
authors.lastname: Ekstrand
authors.forename: Martin
authors.initials: M
authors.lastname: Hägglund
authors.forename: Karolina
authors.initials: K
authors.lastname: Kristenson
authors.forename: Henrik
authors.initials: H
authors.lastname: Magnusson
authors.forename: Markus
authors.initials: M
authors.lastname: Waldén
mesh_terms: D000041:Absenteeism; D001265:Athletic Injuries / Q000453:epidemiology / Q000517:prevention & control; D005060:Europe / Q000453:epidemiology; D006801:Humans; D008022:Ligaments / Q000293:injuries*; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries*; D011446:Prospective Studies; D012916:Soccer / Q000293:injuries* / Q000706:statistics & numerical data
keywords: Epidemiology; Hamstring injuries; Injury Prevention; Lower extremity injuries; Soccer